Sorry the article is in German, but the author basically analyzes spectrum charts provided by the manufacturers for flourescent tubes from Dennerle, Arcadia, JBL and Juwel, and finds that they are identical to the official manufacturer-given spectrum charts for standard tubes from Sylvania and Narva. I know these are Germany/Europe oriented brands, but maybe it is useful for others who happen to be on this side of the pond.

On a related note, I swapped out the two T8 18W tubes in my Juwel canopy with Osram Cool Daylight 835 tubes despite the nice warning on the hardware that says "make sure you ONLY use Juwel tubes!!!". Definitely brighter, and way whiter/bluer light than before. So if you are to take away anything from this, it seems to be that Jewel T8 tubes are a total rip-off and aren't even really suitable lighting for planted aquariums.

I don't know many of those brands, so won't comment there. But to your last point, i have found that most (= all I have tried) of the so-called "aquarium" or "plant" tubes are weak intensity compared to the daylight tubes with a Kelvin around 6500K. These will seem brighter because of the spectrum, having more green/yellow in the mix with the red and blue, but aside from this they are much brighter in actual intensity. Most planted tank authors do recommend tubes around 6500K, for good reason.

The aquarist is one who must learn the ways of the biologist, the chemist, and the veterinarian.[unknown source]

Something we all need to remember: The fish you've acquired was quite happy not being owned by you, minding its own business. If you’re going to take it under your wing then you’re responsible for it. Every aspect of its life is under your control, from water quality and temperature to swimming space. [Nathan Hill in PFK]